I thought Air Force had a very good defense. They weren’t big or super fast, but they were smart and sound—if a defense as a whole could get a nickname I’d call them Ol’ Eleven Kovacses.

Their gameplan was also brilliant. They knew Michigan wanted to run inside the tackles, get Speight some confidence, and get athletes out to the edge, so Air Force came in with a plan to jam up running lanes and make Michigan try to guess where the big hole would be. This is AF’s look on Michigan’s first running play:

They’re in base 3-4 personnel, with both ends lined up in 5-techniques (over the tackles’ shoulders), both OLBs in 7-techniques (over the TE or hypothetical TE’s shoulders) and one safety down at linebacker depth to react to Michigan putting a lineman (Ruiz) at tight end.

Now this is not Belicheck’s mother’s 3-4. That nose tackle was 5’11/260. He certainly wasn’t going to be two-gapping. Rather out of this setup Air Force’s plan was to have the nose attack almost like Brown’s 3-3-5 linebackers, appearing in any A or B gap on any given play and making life hard on Michigan’s inexperienced interior OL to figure out what to do with him.

If that all sounds familiar, it’s because you’re old, and it is:

That’s right: that sonovabitch Calhoun walked into Michigan Stadium and tried to run Bo Schembechler’s defense on us.

1. So what is this defense again?

Last year Michigan moved from the 4-3 under they deployed in Mattison's first three seasons in Ann Arbor to a 4-3 over. DJ Durkin seems set to return Michigan to a defense that's going to seem a lot like Mattison's earlier outfits. Whether you call this a 4-3 under or a 3-4 is mostly a semantic issue. However, it's one that's driving me nuts every time a writer for the Wolverine talks about Michigan's forthcoming 3-4 transition.

"Watching film on Dante (Fowler) and experience this position has been a ton of fun," he said. " The BUCK is like the hybrid on the field. You're sometimes standing up and sometimes have your hand in the dirt. Wherever you're at at that position, you're expected to make plays. You gotta get to the quarterback as quickly as you can and make tackles."

Durkin apparently calls his fancy spot the "buck linebacker." Therefore 3-4. Durkin's buck linebacker last year was 6'3", 260 pound Dante Fowler. Fowler almost always rushed the passer from a three-point stance. Sometimes he would drop into coverage or fold back into a run fit.

In this he is exactly—exactly—like what Michigan did with Frank Clark in the under. We even have a mascot for this, Slanty The Gecko. Slanty was inexplicably the first hit in Google Image Search for "line slant football" and has featured in multiple posts that describe Michigan's nominal weakside end going SYKE LINEBACKER MORPH and dropping back as the SAM plunges willy-nilly into the defensive line. Here is an example:

According to Mattison, Michigan did this on maybe 40% of its snaps from a 4-3 in his first year at Michigan. I'd say the BUCK concept is that only more so, but I don't think it can in fact be more so.

To me the real distinction between a 3-4 and a 4-3 is in your interior line. Are your guys planet-shaped gentlemen? Do you have Louis Nix? You're probably running a 3-4. Do you have Ryan Glasgow? You're probably running a 4-3. People will talk about multiple fronts, and Michigan will run multiple fronts. All of those will be efforts to confuse the offense as they inject their DTs into gaps and get penetration.

The upshot: this is not a big change, if it's even a change at all. It is a nomenclature tweak.

In previous layman's discussions on how fancy newfangled anti-spread defenses function I've talked about how Quarters works, and how MSU used aggressive alignments with it to dominate the run game at the cost of greater risk of getting beat over the top. Each time I alluded to the fact that Saban's defense is similar in concept except where Quarters is a Cover 2/Cover 4 hybrid, Saban's is a Cover 3/Cover 1 hybrid.

We will see it this year. Every defense uses some Cover 3 and Cover 1 as a changeup, but Saban's base system, now all over the SEC, has spread into various Michigan opponents. Penn State kept it around while transitioning to Bob Shoop's version of Quarters. Maryland had it last year; not sure if their 4-3 transition includes a coverage shift. I think BYU (which is going back to 3-3-5 with Bronco Mendenhall overseeing it personally) is expected to as well. Michigan State has played with it, since it's similar to what they do normally. Anyway I thought it'd be fun to get into it now, so we'll have it to reference later.

Pre-emptive thanks to actual football coaches who post in the comments and point out where I got something wrong or over-simplified.

I'm Not a Coach Disclaimer

I'm not a football coach. I'm a guy on the internet who read a lot about football.

Basics of One-High Defenses

Cover 3 is probably the most basic defense in existence. It is the defense you learn on Day 1 as a high school freshman, if not before. At that level it is a "go to this spot and then find work" scheme, past that there are techniques coaches teach to cover the gaps. Here are the two basic versions that Saban uses against standard 2x2 formations:

If you picked up on the fact that "Liz" and "Rip" begin with the same letters as "left" and "right" (or you know your port and starboard colors) you have my permission to eat a cookie.

Joe Paterno used variations of this (Rip is very close to his base defense*) since the Chatelperronian, and like Neanderthal toolkits it only looks crude until you see it in the hands of a master.**

Some things to know that we'll use later:

The receiver numbering system is the same as in Quarters: start from the sideline and work your way in until you're at the center. It's where they are at the snap, not before, in case motion messed with that.

The path you take to your zone matters a great deal. Note how guys running toward their zones are actually going through weak points in the coverage. This is for "routing" purposes: if you're there a receiver can't be.

The latter is true for all zone defenses, but it's a stress point for Cover 3 because the holes in the zone are places the offense can attack either quickly (7-9 yards downfield in the seam) or easily (deep downfield once the free safety has committed). Cover 3 coaches teach defenders to be in the way so receivers have to re-route to covered places.

The tradeoff is natural coverage strength to the middle of the field, to the detriment of the flats—if you've ever watched an NFL defense that seems to constantly be tackling fullbacks squirting out of the backfield, that's why.

The problem with Cover 3 is the same problem with Cover 2: those frikkity vertical routes:

The problem remains with pretty much any set of routes that stem from a vertical release.

The old-fashioned answer to this is play more man defense, and certainly Cover 1 (example diagram) is a complementary coverage to any Cover 3 team. In Cov1, aka "Man Free" defense, corners stay on the receivers, the erstwhile "curl/flat" guys stay on the #2's, and the middle linebacker over the RB takes the RB.

But if you're playing man-to-man defense, you'd better have men who can win their battles 97%+ of the time against theirs. If you need to activate that free safety to double up a dangerman, now you're giving up "front"—how many defenders are participating in your run fits, and once it's not an 8-man front anymore you're weak against the run. Offenses will also use rub routes, or exploit matchups, e.g. have a quick slot receiver sprint across the formation until he loses the linebacker trying to keep up.

These were problems for Saban to a much greater degree when he was dealing with the kind of talent the Cleveland Browns drafted during his DC days. By the time he got to MSU he already had his Rip and Liz and his Cov1 amalgamated into a hybrid scheme he called "pattern matching."

[After the jump]

-----------------------------

* The Paterno-era "Hero", and "Sam" in the linked diagram were early examples of hybrid space players, and the zone-blitzing 8-man front it spawned was the basis of Rocky Long's 3-3-5 defense.

** …who discovered children were being sexually abused in his locker room and didn't tell the police because football reasons.

3-4, 4-3, etc etc

I've said this before and I'll probably say it again several times before the season starts: Michigan is not likely to be moving to a traditional 3-4 system. Nor will they spend a lot of time implementing a traditional 3-4 to mix in with a 4-3. The time commitment to do so is prohibitive at the college level, and the kind of personnel who can effectively do both are too rare.

Sam Webb:Michigan is telling kids that they are going to be basically 50/50 as far as 3-4, 4-3. As best you can without having a visual aid or a grease board, explain to people, how that will come to pass and why Michigan is saying that, why that makes sense.

Ray describes the 4-3 under as something that could be looked at as a 5-2…

Brennen Beyer, the stand-up SAM in this picture, bounced between SAM and DE for his career

…and says that a 3-4 can look a lot like the under. Both accurate, and as I've mentioned before you can look at the under as a defense halfway between the traditional Miami-style 4-3 even/over and a 3-4.

But I think the distinction here is a bit of a red herring. I asked Spencer Hall what Florida ran last year and he replied it was a 4-3 with a standup end (Dante Fowler); my observations of the Florida defense rarely encounter a nose tackle lined up directly over the center. He's almost always in a gap.

Could it shade to a 3-4? Sure, I guess. Why would they do that? There are two reasons:

To run a 3-4! Obviously.

To disguise their 4-3. Gap-sound unpredictability is a major goal of all defenses. Putting a nose tackle over the center gives him an advantage if he's going to slant one way or the other, but the idea is still the same: get in a gap.

Ray explains:

"If you line up in that A gap or that center believes that they know you have this gap then it is easier for them to block you because you‘re more of a standing target, they know what gap you’re responsible for, but in that 30 front, you can slant and angle in either way. They don’t know which gap you are responsible for and they have to guess and try to figure it out once the ball is snapped, but it gives the D-lineman the flexibility to go either way. And then let the truth be told, in that same 30 front, if you have a noseguard that is lined up right over the center and he slants to the strong side, then that is technically going back to under. If that noseguard slants to the weak side, in the weak side A gap, then that technically puts you in an over front, because the entire front has to shift along with him, so now that gives you some 4-3 flexibility from a 30 front if you just slant and angle, it puts you right into a 4-3 defense.”

If you believe that Ryan Glasgow will hold the nose tackle job, a 30 front featuring him is an undeclared 4-3. Michigan doesn't have a Nix or a Gabe Watson to hold down the middle of that defense and two-gap the center unless Ondre Pipkins goes from afterthought to superstar in his final year or Bryan Mone is terrific as a sophomore.

Michigan may run a bunch of different fronts but at its heart the defense is probably a 4-3. And judging from Florida last year it's not going to seem that much different than Mattison's fronts.

Defensive Line

Lawrence Marshall is a name to watch. [Bryan Fuller]

Anyway this is all a lead-in to an assertion that for now I'm still assuming Michigan has a traditional 4-3 look this fall and I won't be changing up the nomenclature yet.

If and when we get enough data to do so it looks like the first change will be at WDE, which Florida folks sometimes call "drop end." Reports hold that Mario Ojemudia and Lawrence Marshall are frequently in a two point stance—something Marshall had never done and was taking some time adjusting to—this fall. Again, this gives the impression of a 3-4. In my mind it's taking the Mattison 4-3 under a half-step towards a 3-4 but whatever.

Marshall is doing well. His athleticism stands out and he's already about as big as Ojemudia. Ojemudia had to put on a bunch of weight and topped out around 250; unfortunately he hasn't displayed the explosiveness he had in high school at the bulkier number. A platoon is certain… unless Marshall wrests the job away and Ojemudia is again called upon to be a guy who plays spot downs to rest the starter. Michigan is trying out the occasional linebacker there as well, with Royce Jenkins-Stone the most prominent.

The other three spots have seen a ton of rotation, some of it involuntary. Injuries have held out big chunks of the line for a practice or three. When present, Willie Henry has been impressive. Chris Wormley is playing SDE again($), which makes sense given the depth chart (especially with Henry Poggi trying his hand at TE, and double especially if Michigan is moving back to more of an under). 4-3 under SDE is a better fit for him, as he can be that RVB type with a bit more pass rush.

Linebackers

There's as of yet no movement away from the presumed lineup of senior starters: Ross, Morgan, Bolden. With Greg Mattison still around I'm not surprised. 247 does mention a competitor to the presumed starters($):

[Ben] Gedeon has popped out early as a potential contributor in this year's defense. He has potentially the best combination of size, athleticism and intelligence at the position and it might turn into a situation where it's difficult to keep him off the field. For the second straight season, linebacker may be Michigan's deepest position, so if he stays on the field consistently, it will be because he's turned into a good to great player.

True junior Gedeon is a prime member of Team Why U No Redshirt who needs to start making an impact now. Michigan has rotated extensively in the past—not so much last year—and I expect he'll get playing time almost in line with the starters.

That is about all the chatter, with Ross/Bolden/Morgan the presumed starters. They look good when the DL isn't having them catch blocks all day, which has been something of an issue since a lot of guys have been out.

Secondary

There have been plenty of reports on Jabrill Peppers, who is looking like the Jabrill Peppers everyone dreamed about when he committed. Peppers bounces from safety to nickelback and looks like Jabrill Peppers should. He is taking ownership of his unit even as a sophomore:

"He's a high energy, high motor guy and he's going to talk trash," Countess said last week. "And he's going to get everybody going. He's been one of those guys you want on the field.

"Even if he has a bad play, he's going to let you know. And if he has a good play, he's definitely going to let you know."

Countess loves the energy and the intent. But when asked if there is ever a time when he'd like to have the ability to quiet his younger teammate, he's quick with an answer.

No way.

"I love it," he says with a smile. "He says the stuff that I don't say, but everybody's thinking."

As Michigan State demonstrated last year, one of the most important positions on the field as an aggressive defense going up against spread offenses is the slot-side safety. He often gets tested deep in cover four.

It'll be interesting to see how Michigan aligns. I'm guessing Peppers just gets the field side as they rely on the restricted space to help Jarrod Wilson out. An observer from the coaching clinic did note that Peppers is usually "aligning to pass strength," so that is encouraging in terms of keeping Wilson in a FS-ish role he's comfortable with and maximally utilizing Peppers's skills.

Jourdan Lewis is also drawing consistent praise. He was Michigan's #1 corner by midseason last year, passing both Countess and Taylor; it sounds like he has picked up where he left off plus a little bit of tackling strength. With Blake Countess set to be a four-year starter the top four guys in the secondary are pretty set. The main question is: can Countess bounce back from some rough times last year and play man to man? 247 has heard he is in "lockdown" mode, so there's that. I'm reserving judgment.

Freddy Canteen is getting a few reps at CB, so… that's odd. Harbaugh loves flipping guys around to see what they can do, and Canteen is a guy who could theoretically be a good corner. Doubt it sticks, but whatever.

Notre Dame has a very good defensive line, possibly great. If they still had Aaron Lynch holy pants man. They don't, but Tuitt is a 300 pound pass rusher, Nix is hard to move, and their Kapron Lewis-Moore/Prince Shembo combo at the other DE is a quality option. They've been making a lot of plays so far, and some of them against Lewan, who has a bunch of NFL hype and has shut down virtually every DE he's ever gone up against, including guys like Adrian Clayborn.

So Michigan was up against it against the Irish. They compounded those troubles with a spate of seemingly bizarre play calls that made it even harder for Michigan to execute since they often left key players unblocked, with the results you saw.

Here's a two yard run in the second quarter. It's first and ten on the first play of Michigan's first drive after the Smith interception. ND comes out showing a four-man front with one-high coverage, but will shift into their standard 3-4. Zeke Motta, currently 16 yards off the LOS, will approach the LOS for an eighth run defender against eight players in the box.

Post-shift, this is about standard for ND. Note that the secondary is showing extremely soft man coverage on the receivers, which is par for the course when you are in cover zero with three converted offensive players. Or at least, I'd imagine it's par for the course if anyone else ever did this.

Now, you may be thinking "AAAAAH DAMN AAAH BUBBLE." I am too. The defense is allowed to align like this because Michigan won't take a shot at that gooey soft edge. Constraint plays constrain what a defense can do, simplifying life for QBs. Here we've got a play, and it's a run despite the D showing a cover zero look.

This was supposed to be a midline type read. When ND showed a four-man front, Nix was shaded outside of Mealer. He would hit the frontside A-gap, allowing Barnum to release into the second level. Instead he's head up on the center and fights back, forcing Barnum to try and deal with him.

What Michigan thought it was doing

Meanwhile, Lewan's flare out on Shembo was supposed to be useful. Instead he's blocking a contain guy on a run up the middle. Lewis-Moore is not tearing up in a gap like a one-gap DL would but coming upfield under control.

So instead of a quick hit that got Michigan past the DT they get this:

Which is two yards thanks to an unblocked LB in the middle of where your belly is supposed to go.

Video:

This Looks Familiar

Denard's second interception is a terrible throw helped along by a totally unblocked Te'o as Barnum tries to help on Nix.

Terrible throw and all that but also not a shining example of coordinator mastery. This is a position to fail in, when you can't step into your throw because you'll get hit if you do so.

Things and Stuff

RB angle gives you the intended hole. Look at how vertical Toussaint is going. This is designed to go backside.

Checks: none. Once ND shifts to the three-man front, this play is in trouble, and once Motta slides down you're up against zero safeties. This would be a nice time to check. To what? Well, you are maybe probably getting some yards if Lewan changes his assignment and releases directly into that LB, or, you know…

…that OLB has eyes only for the backfield, so you've got one guy within twelve yards of the slot receiver. Who isn't a slot receiver, sure.

Since this was the first play of the drive I assume there was time to do this after the shift; nothing comes. This might be on Denard, or there just might not be a check for this. Rodriguez took that check burden onto himself with those plays where Michigan would call for a snap and then everyone would look to the sideline.

Constraints: none. A little later Michigan will block a QB sweep well but Motta will show in the hole as an unblocked eighth guy. Denard will abort and get three. ND again went cover zero with pudding soft outside coverage:

They're sitting out there waiting to give you their money! It's not the stupid little bubble itself that helps—though the yards from 2-8 averaging about 6 aren't bad—but the things that the defense can't do because they can't align with their secondary in Bolivia and bring down a run defender that erases your numerical advantage.

This alignment cannot be allowed to exist without a quick easy throw that invalidates it. Have we mentioned that both corners are converted offensive players? And one is a freshman?

Oy OL. Note that Nix not only drew a double but ripped through it to the backside hole, and that Tuitt has gotten inside of Schofield with ease. It may have been possible to get some yards here by getting Nix sealed and hitting a gap further to the playside, but none of that happens. I haven't gotten to the bit where Michigan just grinds on them yet, but so far there have been a lot of plays like this where Michigan OL get nowhere with their guys.

Why are we running a play that seems designed to go at a 4-3? ND will go to it but they are a 3-4 at heart and when they show a four man line it's usually short yardage or a passing down. I would expect an incoherent play like this to fire off when ND is giving Michigan a 4-3 curveball instead of the 3-4, especially after Michigan spent two weeks preparing exclusively for this defense. That Lewan flare-out is deadly to this play because Barnum has to help on a NT who is not shaded—and is rarely shaded. Meanwhile that guy on the edge is not a threat to Toussaint. RPS –1.

Brian,
Do you think the recent schedule announcements that have us playing more quality non conference opponents are in anticipation of the selection committee favoring teams with a quality strength of schedule?

Scott

To me it seems more like an economic thing than an attempt to gain a competitive advantage. One of the benefits of being squeezed hard—or at least having a subsection of the fanbase that is now dumping millions of dollars into club seats and suites—is those fans are now expecting more for their money. As the price you're asked to pay for tickets approaches its value to you, improvements in the product matter. Eight years ago it didn't matter who Michigan scheduled as long as it was a home game. That's no longer the case, or at least it's close enough that the AD doesn't want to take chances.

Combine that with rising rates for tomato cans and the importance of television and college football's economics are moving back towards having more real games.

That said, I do think a schedule like the 2015 slate is a good one if you're good enough to be in the playoff discussion. If that's the case you should be beating the two Pac-12 teams you've signed up, and that may give you the edge over a team from another conference that played East Nowhere. Brandon is due credit for the way he's set up the next few years of nonconference games. Hopefully he secures a home and home worth interrupting the Notre Dame series for in the near future.

Money gap == performance?

Brian,

I’ve seen several of your entries over the months talk about the growing financial disparity between the B1G and the rest of the BCS conferences. By all accounts the BTN has been a success and helped put the B1G on very sound financial footing, and has kept the other BCS conferences scrambling to find a way to match revenue (realignment, renegotiated TV contracts, etc.)

I don’t have any numbers, but I’m guessing that the B1G is about to enter a brief period where their revenues will outshine everyone in the BCS conferences and that gap will grow. Do you think this financial advantage will ever lead to a competitive advantage in football? Could more revenues, funneled down to the league members, create some national championships?

FWIW, I spoke with my brother (U-M grad and fan) about this and his opinion is that this might show up more in the middle and bottom of the league than at the top. Basically he says that seedy coaches, even seedier alumni boosters, regional talent bases and an obsessive focus on football can trump the money advantage.

What’s your take?

Pete

If we're talking about the will to power here, don't you think we would have already seen some of that impact? Minnesota and Illinois aren't reaching deep into their pockets to hire a Mahlzahn or similar, they're making the same hires they always have when they're not hiring patently unqualified nutcases: guys who've done well in the MAC. Northwestern's married to Fitzgerald for a long time, Iowa's going with Ferentz, Bill O'Brien was not exactly a power move by Penn State (though he is recruiting well out of the gate in trying circumstances)… the easiest and most legal way to flex your dollars is by hiring big time coaches, and the middle and bottom of the Big Ten aren't doing that.

It's actually at the top where we're seeing that money spent in buckets. Michigan hired a did-well-at-lower-level type coach but paid him handsomely, and now they're giving both coordinators SEC-type money. Ohio State paid Urban Meyer a ton of money to rescue them from tatgate. The only middle-of-the-road program that is using money to its benefit is Michigan State, which is managing to hold onto its DC for another year or two by paying him mad money. And even the Spartans have seen big chunks of their coaching staff leave—it's one reason MSU hasn't been able to get a high profile instate guy without huge grade question marks since Hoke arrived.

Part of this is just the attractiveness of the job. Is Sexy Coach X confident he can make waves at Minnesota? Probably not. He's worried that his front teeth will start growing… and that he'll end up like Glen Mason in the best case scenario. There's only so much dollars can buy you when the alternative is almost as many dollars and a better shot at long term-dollars (and success).

I don't think the Big Ten's lead in money is going to make for a noticeable competitive advantage. The margins aren't that high. The SEC dumped $18.3 million on its member schools last year, the Big Ten $22.6. That gap narrows once third-tier rights—which Big Ten schools have signed over to the BTN and SEC schools do get some money out of—are considered, and narrows even further when you spread that bounty over two dozen sports that are all clamoring for something. The money advantage is washed away by having more local talent and more dudes willing to ply that local talent with other local talent.

My long term Big Ten dominance hope: global warming.

But seriously folks, the Big Ten is going to be better in the future. Penn State no longer has the Paterno millstone around their neck, OSU isn't going anywhere, and Michigan will in short order be This Is Michigan again. A large part of the conference's reduced standing in recent years has been because the big powers weren't pulling their weight, and it looks like that's coming to a close. Add in Nebraska and more equal footing is coming. Perfectly equal? Probably not.

Yes, I'm going to keep answering this until people stop asking me about it.

I was wondering if you could explain the advantages to using the 4-3 over the 3-4 this year. Although I understand the theory behind the different systems, it seems like Michigan's depth and more proven talent is at linebacker. Instead of having two unproven guys up the middle in Black/Washington and Campbell/Ash/Pipkins, why not line up with the best space-filler of the DT's, and then have Morgan, Demens, Bolden/Hawthorne/Gordon (the best of the three), and Ryan all lining up at LB. This would give us an option with fewer question marks and would allow Mattison to have some more fun with his blitz packages, which can generally be far more varied in 3-4 systems than in 4-3.

Bill

There are three main reasons Michigan's going with the 4-3 under this year.

ONE: IT IS GREG MATTISON'S DEAL, MAN. When I checked out Mattison's presentation at a Glazier Clinic earlier this year, he briefly paused at one point and said something along the lines of "if you think you can defend with three linemen, God bless you, but at Michigan we're using four. We'll be here for hours if you want to debate with me." Mattison's a 4-3 guy, especially on the college level. Asking him to run a 3-4 is not playing to his strengths. See: GERG 3-3-5.

TWO: IT IS THE SAME THING AS LAST YEAR. The last time Michigan went into a season with the same defensive coordinator running the same defense he ran the year before was 2007. That was forever ago, and we have felt the pain since. With most of the defense returning it makes sense to tell them to do the same things they were doing last year. Remember how much better Jake Ryan got at not screwing up as the year progressed? You're tossing some of that away by changing defenses.

THREE: IT DOESN'T ACTUALLY SOLVE ANY PERSONNEL PROBLEMS. The most obvious difference between the two systems is in what they ask the linemen to do. Michigan's one-gap 4-3 under generally asks defensive linemen to pick one spot between two linemen and attack it. Traditional 3-4s want all three defensive linemen to control the blocker opposite them and be able to come off on either side of the guy when the ballcarrier gets to them.

If that latter task sounds like it requires a big strong guy, yeah. The best example is Alabama's Jesse Williams, the Australian swamp beast who is moving to nose this year. This guy played DE for Alabama:

That is the kind of guy who occupies all three line slots in a 3-4.

Craig Roh is not a swamp beast. Nor is Jibreel Black. In a 3-4, those guys are either moving to outside linebacker or wandering Europe like a stateless refugee in WWII. They don't really have a role. Meanwhile, the WDEs all get drafted at OLB, leaving you with three spots to fill with tanks instead of one and a half.

The 3-4 is kind of an all or nothing setup, with 300+ pound guys who can squat dump trucks on the DL, Lamarr Woodley sorts at OLB, and traditional ILBs. In contrast the 4-3 under has a smooth size gradation from nose to three-tech to SDE to WDE to SLB to MLB to WLB. In a year when Michigan's not even sure if they've got one nose tackle, a 3-4 essentially asks them to have three.